Wireless mesh network

From Wikipedia, the free encyclopedia

You have new messages (last change).

This article or section is in need of attention from an expert on the subject.
WikiProject Computer networking or the Computer networking Portal may be able to help recruit one.
If a more appropriate WikiProject or portal exists, please adjust this template accordingly.

Wireless mesh networking is mesh networking implemented over a wireless LAN.

Whereas the Internet is mostly a wire-based, co-operative electronic communication infrastructure similar to the international postal agreement, in that messages are mutually delivered and relayed within their separate domains free of charge (i.e. if you relay my messages within your domain I'll relay yours within mine), Mesh is a wireless co-operative communication infrastructure between a massive amount of individual wireless transceivers (i.e. a wireless mesh) that have Ethernet type capabilities.

This type of infrastructure can be decentralized (with no central server) for less scalable applications or centrialized controlled for high scalable applications (with a central server), both are relatively inexpensive, and very reliable and resilient, as each node need only transmit as far as the next node. Nodes act as repeaters to transmit data from nearby nodes to peers that are too far away to reach, resulting in a network that can span large distances, especially over rough or difficult terrain. Mesh networks are also extremely reliable, as each node is connected to several other nodes. If one node drops out of the network, due to hardware failure or any other reason, its neighbours simply find another route. Extra capacity can be installed by simply adding more nodes. Mesh networks may involve either fixed or mobile devices. The solutions are as diverse as communications in difficult environments such as emergency situations, tunnels and oil rigs to battlefield surveillance and high speed mobile video applications on board public transport or real time racing car telemetry.

The principle is similar to the way packets travel around the wired Internet — data will hop from one device to another until it reaches a given destination. Dynamic routing capabilities included in each device allow this to happen. To implement such dynamic routing capabilities, each device needs to communicate its routing information to every device it connects with, "almost in real time". Each device then determines what to do with the data it receives — either pass it on to the next device or keep it. The routing algorithm used should attempt to always ensure that the data takes the most appropriate (fastest) route to its destination.

The choice of radio technology for wireless mesh networks is crucial. In a traditional wireless network where laptops connect to a single access point, each laptop has to share a fixed pool of bandwidth. With mesh technology and adaptive radio, devices in a mesh network will only connect with other devices that are in a set range. The advantage is that, like a natural load balancing system, the more devices the more bandwidth becomes available, provided that the number of hops in the average communications path is kept low. Additional information by can be seen at the original patent description for mesh wireless networks at http://www.delphion.com/details?&pn=WO09608884A1 giving the mesh technology designs.

There are three distinct generations of wireless mesh products today. In the first generation one radio provides both backhaul (packet relaying) and client services (access to a laptop). In the second generation, one radio relayed packets over multiple hops while another provided client access. This significantly improved backhaul bandwidth and latency. Third generation wireless mesh products use two or more radios for the backhaul for higher bandwidth and low latency. Third generation mesh products are replacing previous generation products as more demanding applications like voice and video need to be relayed wirelessly over many hops of the mesh network.

[edit] Protocols

There are more than 70 competing schemes for routing packets across mesh networks. Some of these include:

The IEEE is developing a set of standards under the title 802.11s to define an architecture and protocol for ESS Mesh Networking.

A more thorough list can be found at Ad hoc routing protocol list.

[edit] See also

[edit] External links

  • What is Third Generation Mesh? Review of three generation of mesh networking architectures.
  • CUWiN.Net Mesh network documentation for CUWiN networks
  • Roofnet.net Mesh network documentation and monitoring for MIT-based roofnet networks
  • Moskaluk Wireless Mesh Don Moskaluk Mesh network documentation and monitoring for Locustworlds Open Source AODV
  • NetEquality A non-profit building mesh networks for low-income neighborhoods
  • IET From hotspots to blankets
Retrieved from "http://en.wikipedia.org../../../w/i/r/Wireless_mesh_network.html"
In other languages